Telephone-exchange system



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Aug; 25, 1925. ,1,550,314

\ L. H. JOHNSON TELEPHONE EXCHANGE SYSTEM Filed Aug. 2l, 1923 I miranti.

Patented .i1-tus. 25, 1925.

T 0 F F l C E LEWIS H. JOHNSON, OF MADISON, NEW JERSEY, ASSIGNOR TO 1i/VESIEIRN ELECTRIC COMPANY, INCGRPORATED, OF NEW' YORK, N. Y., A CORPORATION 0F NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed. August 21, 1923. Serial No. 658,511.

10 all whom t may concern:

Be it known that l, Lewis H. JoiiNsoN, a citizen of the United States of America, residing` at Madison, in the county of Morris and State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to systems employing selectively operable automatic switches for extending a call from a calling to a called line.

In such systemss it is well known practice. to operate a meter associated with the calling line in case of a successful call in order to charge the calling subscriber for the` servicc rendered. In my copending application, Serial No. 661,031, filed September' 5, 19:23, I have disclosed means for periodically operating the meter of a calling line during the conversational period to more equitably charge the subscriber for service, the amount of the charge. or the number of times the meter is operated being determined by the. length of the period the calling subscriber holds the established connection after the response of the called subscriber.

It is further desirable in large exchange areas to regulate the amount of the charge for each unit period of conversation in accordance with the location of a called line in the exchange area with respect to the calling line or in` accordance. with other traffic conditions.

It is therefore an object of the invention to provide an arrangement of circuits in an exchange system, by which the charge recorded by the meter of the calling` line for each peri-od of conversation is automatically varied in accordance with the character of the call.

This object is accomplished in the specific embodiment of the invention shown, by

dividing the subscribers lines .of the eX- change area into Zones and differentiating the subscribers lines in different Zones by one or more of the digits of their designations or call numbers. The action of dialing orotherwise transmitting the number or a wanted line which initiate-s a series of operations to effect the extension of a connection to the wanted line, also effects the variable operation of a mechanism for con trolling the metering device of the calling line in accordance with the Zone in which the called line is located.

A feature of the invention involves the use of a timing sequence switch which completes a cycle of operation once for each unit period of conversation, and which effects the operation of the calling line meter one or more times during each cycle, in accord ance with the zone designation of the called line as established through the operation of the central oiiice sender.

A. specific feature of the invention further involves an arrangement of circuits in conjunction with the timing sequence switch such that the number of times the calling line meter is operated during` each cycle of operation of the switch is determined conliointly by the position into which the district sequence switch is set for talking and by the class of service setting of the central ofhce sender.

Other objects and features of the invention will be apparent from the following detailed description considered in` connection with the accompanying drawing which represents diagrammatically, portions of a full automatic exchange system embodying the present invention.

The line finder, brushes only of which have been illustrated at 105, may be of the general type disclosed in the patent to J. L. McQuarrie No. 1,177,044., issued March 28, 1916, and functions in the manner set forth fully in a patent to F. S. Irvine, No. 1,461,- 528, issued July 10, 1923. The district selector, brushes of which are indicated at 125 and the sender shown in the dotted rectangle in the lower right portion of the drawing may be of the general type disclosed in the patent to F. A. Stearn and F. J. Scudder No. 1,395,977, issued ,November 1, 1921. The other selector switches, by means of which a connection may be completed to the line of a wanted subscriber, have not been disclosed herein, but may be of identically the saine type as shown in the patent to F. A. Stearn and F. J. Scudder above. referred to.

For controlling the circuits of the line finder 105, and district selector 125, a sequence switch 109 of the well known type is provided. Certain of the cams of this sequence switch have been illustrated above the dotted lines 0f the drawing. A second sequence switch is illustrated at 140 and controls the cams shown within the dotted rectangle in the lower lett portion of the drawing. This sequence switch is individual to the district selector 125 and Yfunctions as a timing` switch to control the operation of the calling` line meter.

A ratchet wheel relay is disclosed at 146 which functions under the control of a clock relay 1411- or counting ed a definite time interval to control the movement of sequence switch 140. This ratchet wheel relay comprises a magnet having a low resistance operating wind-` ing and a high resistance non-inductive winding. The magnet ot the relay controls two armatures, one having a stepping` pawl 156 associated therewith and the other having a holding pawl 157. both cooperating with a ratchet wheel which carries a contact closing cam. Current flowing` through the operating winding is suiiicient to attract both armatures, and current through both windings while sufiicient to maintain the holding armature attracted when it has once been operated, is not suliicient to initially operate either armature. Vhcn current is cut-olf from both windings o1' the relay, both the stepping pawl and holding pawl are released from the teeth of the ratchet wheel and the ratchet wheel is returned to normal position by means of a spiral spring.

It is believed that the invention will be best understood from a detail description of the manner in which the disclosed circuits and apparatus function. When the calling subscriber at substation 100 initiates a call by removing his receiver from the switchhook, a loop circuit is closed over the line conductors 101 and 102 through the back contacts of the cut-011 relay 108 to ground and to grounded battery through the winding` oic line relay 104:. respectively. Tn the well known manner, the line relay 1011 initiates the hunting movement of the line finder 105 in search of the terminals of the calling line. When the calling line is found. a circuit is established from battery, through the right winding of relay 106, to ground through the left contact of cam 128, whereupon relay 106 energizes and establishes a circuit for relay 107. This circuit may be traced from battery, through the lett armature of relay 106, the upper contact of cam 108 to ground through the winding of relay 107. Vith relay 107 energized, a circuit is established from battery, through its right contact over the lowermost brush of line inder 105, to ground through the winding` of cut-ott' relay 103. The cut-oit relay 103 energizes, disassociating the line relay 104 and Iground from the conductors of the calling line. Relay 107 also inthe well known manner causes the advance of the district sequence switch 109 from normal position 1 into position 2.

lith district sequence switch 109 in position 2, the sender selector switch 110, wipers ot which are indicated at 112, 117, 123 and 124 is operated to search for and associate an idle central oiiice sender with the calling line.

When such an idle sender is found, the district sequence switch 109 is advanced into position 3 ior controlling the group selection movement of the district selector 125 in the well known manner. The conductors 101 and 102 of the calling line are now connected over the two upper brushes of the line linder 105,` the lower lett contacts of cams 115 and 1141, conductors 116 and 113, wipers 117 and 112 ot the sender selector 110, to ground and battery through the balancing coil 118, and the pulsing relay 111 of the selected sender. The calling subscriber may now proceed to operate his dial 119 to record upon the registers of the sender the designation of the wanted line.

As soon as the oiiice portion ot the line designation has been recorded upon the sender registers, the district selector 125 is operated to extend the connection to the desired district or otlice of the exchange area in the well known manner. The setting of the district selector is under the control ot the sender steppingl relay 120 and the usual counting relays of the sender, the last one of the series of counting relays being indicated at 121.

Following the setting` ot the district selector 125 and the selection o1 an idle trunk extending to the proper district or oi'lice of the exchange, the district sequence switch 109 is advanced into position 9. in which position the control circuits ot the sender are extended over wipers 123 and 1241 ot the sender selector 110 and contacts of cams 126 and 127 and brushes of the district selector 125 to the selected incoming selector. The sender then proceeds to control the setting ot the incoming` selector and the final selector in accordance with the numerical portion of the line designation recorded on the registers of the sender to extend the connection to the wanted line in the well known manner.

iVhen the connection has been completely established to the terminals of the wanted line. the incoming selector advances the sender causing the advance of sequence switch 109 ot the district selector out of position 9 into position 10. As soon as sequence switch 109 leaves position .9i/2, the conductors 113 and 116 extending from cams 1111 and 115 to the oflice sender are disconnected from conductors 101 and 102 of the calling' line and conductors 101 and 102 are extended over the right contacts of cams reina-leer.

115 and 114 to the left windings of repeating coil 158 and through the winding of supervisory relay 129. Supervisory relay 129 now energizes over the calling line loop and at its contact, establishes a holding circuit tor relay 106 extending from battery, through the right winding ol" relay 106, contact of relay 129 to ground at the right front contact of relay 106. F rom position 10, sequence switch 109 is advanced under the control of the oliice sender into either position 11 or 12 for establishing a talking circuit. Whether the sequence switch stops in position 11 or 12 is determined from the oilice sender in accordance with the class of the call established as determined by the oilice designation of the wanted line. The oiiice sender register relays control the selective movements of district sequence switch 109 for the purpose of altering the connections ot the repeating coil into the talking circuit. In the patent to F. A. Stearn and F. J. Scu-dder, referred to above, district sequence switch 200 corresponding to applicants sequence switch 109 controls the alteration of connections to the repeating coil into the talking circuit. The oltice sender is thereupon dismissed from the established connection.

Following the establishment of the connection to the wanted line, ringing current is applied to the line in the well known manner until the called subscriber responds, when a circuit is established tor energizing the polarized relay 130 at the district selector. pon the energization of relay 130 a circuit is established from ground over the upper right contact of cam 128, the contact of relay 130, the contacts of cam 131, winding of relay 132, the lowermost contact controlled by interrupter cam 133, as soon as the cam 133 reaches such a position as to close the lowermost contact and open the upper contact controlled thereby. Relay 132 upon energizing, locks over its inner right armature to battery, and is therefore maintained energized independent of the contact of cam 133 so long as the called subscriber retains his receiver ofiq its switchhook. As soon following the energization of relay 132 as the cam 133 closes its upper contact, a circuit is established from ground over the upper contact of cam 133, outer right contact of relay 132, to battery through the winding of the charge relay 134. Relay 134 thereupon energizes and locks over the contacts ot cam 135 to ground at its right armature and contact and is maintained locked until the calling subscriber initiates the release of the connection.

With relay 134 energized, and sequence switch 109 in either position 11 or 12, a circuit is established for relay 136 extending from battery, through the left contact ot relay 106, the right contacts of cam 108, inner leit contact of relay 134, upper right and lower left contacts of cam 137 to grolinid tl'irough the left winding ol' relay 136. Relaf7 136 energizes in this circuit and at its lett armature and front contact establishes a circuit over the upper right contact ot cam 133 and through the magnet winding` ot sequence switch 140 to battery, for advancing the sequence switch 140 out oi its normal position 1 After leaving position 1, sequence switch 140 is advanced directly into position 17 over a circuit established by its master cam contact 141. As soon as sequence switch 140 leaves position 1, the previously traced energizing circuit of relay 136 is opened and relay 136 deenergizes.

As the sequence switch 140 advances from position 1 into position 17, the cam 143 establishes a series of metering circuits, one or more of which are eilective dependent upon the position in which the district sequence switch is standing at the time, and upon the energized or deenergized condition of relay 151, as will later appear. lt will first be assumed that the district sequence switch 109 is standing in position 11 tor establishing` a talking circuit to a wanted line which is located in zone 1 ol' the exchange area, and that relay 151 is not at the time energized. When, therefore, sequence switch 140 passes through positions 2 to 4 inclu-sive, a circuit is established for the calling line meter 142, which may be traced from battery, through the left contact of relay 106, the right contacts ot cam 108, the inner left contact of relay 134, lower lett contact of cam 143, nent to the lowermost brush of line linder 105, back cont-act of line relay 104, winding of meter magnet 142 to ground at the outer left contact of cut-oli' relay 103. The meter magnet 142 is energized and as soon as sequence switch 140 leaves position 4, becomes deenergized to record ay single charge against the calling subscriber. `When sequence switch 140 passes through positions 6 to 8 inclusive, the circuit for the meter magnet 142 then eX- tends through the lower right contact ot cam 143, the outer leit contact of relay 134 to the lower left contact of cam 108, but is open at this cam contact since it hasl been assumed that sequence switch 109 is in position 11. A further operation ot meter 142 is therefore not effected at this time. Similarly, when the circuit of the meter becomes extended over the upper contact or cam 143 during the passage oi sequence switch 140 through positions 10 to 12 inclusive and again in positions 14 to 16 inclusive, the meter is not further operated since this circuit is open at the left contact of relay 151. Thus, during the movement of sequence switch 140 from positions 1 to 17 with sequence switch 10S) in position 11 for a call to a wanted line in Zone 1, the meter of the calling line is operated but once.

As soon as sequence switch 140 leit position 1, and moved into position 2, a circuit was established over the left contacts of cam 145 through the winding orp clock r-clay 144 to battery through the clock circuit of the exchange, and relay 144 was therefore caused to operate intermittently under the control of the clock. Also, a circuit was established from battery over the upper contact of cam 147 through the lower low resistance operating winding orp ratchet-wheel relay 146 and to ground through the upper high resistance non-inductive winding ot the ratchet-wheel relay. Due to the inclus sion of the high resistance upper winding and the other resistance elements indicated in the circuits et its windings, the armatures oic the relay are not attracted until the clock relay 144 closes its contact, when the high resistance upper winding of relay 146 be comes shunted over the circuit extending from ground through the upper winding of relay 146, the left armature and contact of relay 132, to ground at the contact of relay 144. With its upper winding shunted, sutiicient current iiows through the operating winding of relay 146 to attract both its armatures, thereby advancing the ratchet wheel one step and holding it in the advanced position. llilhen the clock relay 144 deenergizes, in response to the action of the clock. the shunt is' removed from the upper winding` ot relay 146 and the stepping pawl 156 is thereupon released, but sufficient current flows through the two windings of the relay to maintain the holding pawl 157 in engagement with the teeth of the ratchet wheel. In this manner, the ratchet-wheel relay functions step-by-step from the time sequence switch 140 is advanced into position 2 or immediately `following the response of the called subscriber, and continues in operation until it has completed a complete revolution and the cam ot the ratchet wheel closes the spring contacts 148 unless in the meantime the called subscriber restores his receiver. This period, during which the ratchet wheel is rotated a complete revolution is so determined as to count oiil a conversational period to which the calling subscriber is entitled for a single unit charge.

As soon as the contact 148 is closed by the cam of the ratchet-wheel relay, a circuit is established from battery over this Contact to ground through the lett winding of relay 136, whereupon relay 136 energizes and locks temporarily from battery, through its right winding and right Contact, the lower right and upper lett contacts of cam 137, the left contact or' relay 132 to ground through the high resistance upper winding of relay 146. If the clock circuit is closed at this time, relay 136 locks to ground at the contact of clock relay 144 instead o'r' locking through the high resistance winding of relay 146. In attracting its lett armature, a circuit is established from ground over this armature and front contact and the upper right contact of cam 138, tor advancing sequence switch 140 out ot position 17 into position 18. As soon as sequence switch 140 leaves position 17, the circuit previously traced from battery over the upper contact of' cam 147 through the windings of relay 148 is opened and both pawls 156 and 157 of the ratchet wheel become disengaged from the ratchet wheel permitting the restoration of the ratchet wheel to normal position and the opening of contact 148. lilith contact 148 opened, the initial energizing circuit of relay A3G is opened and due to the high resistance of the holding circuit or' relay 13G, this relay becomes deenergized after an interval closing at its lett armature and back contact a circuit extending from the lower contact of cam 138 and through the winding ot sequence switch magnet 140 for advancing the sequence switch out of position 18 into normal position.

it' the conversation still continues at the time the relay 146 has completed one cycle of' operation and the sequence switch 140 has become advanced to position 1, the circuit is again established as previously traced through the left winding of relay 136, the lower left and upper right contacts or' cam 137, the inner left contact of relay 134, the right contact-s of cam 108 to battery at the left contact of rela-y 106, and relay 13G upon energizing again advances the sequence switch 140 out of position 1 from which position it continues moving into position 17. As the sequence switch again passes through positions 2 to 4 inclusive, the calling line meter is again operated. In this manner, the meter 142 is operated once for each revolution or switch 140 until the calling subscriber restores his receiver to its switchhook. It during any cycle or' operation ot ratchet wheel relay 146, the called subscriber restores his receiver to its switchhoolr, the circuit through the operating winding of relay 146 is interrupted at the lett contact of relay 132 and the advance of the ratchet wheel relay is thereupon arrested. It is held in its advanced position however over the holding circuit extending through both windings ot the relay and the upper contact of cam 147.

Villien the calling subscriber restores his receiver to its switchhook for releasing the established connection, relay 129 becomes deenergized in turn opening the holding circuit of relay 106. Relay 106 at its lett contact opens the initial energizing circuit of relay 107, but this relay is maintained energized over the lower contact oi' cam 147, until sequence switch 140 reaches position 17, when relay 107 deenergizes opening the circuit of cut-oil relay 103. rlhis insures that the calling subscriber will be charged for any completed unit period of conversation. Upon the deenergization ot' relay 106, a circuit is closed from the normal contact of its right armature, cam Contact 152, to battery through the winding of relay 153. Relay 153 thereupon energizes and closes a circuit from ground over the commutator segment 154 of the line finder 105, through the contact or' relay 153, the upper left and lower right contacts of cam 155, and to battery through the magnet winding of sequence switch 109 for advancing the sequence switch out of talking position in which it is resting into position 16. Upon the deenergization of relay 107, a circuit is established from ground at its left back contact, through the upper leit contact of cam 188, to battery through the magnet winding of sequence switch 140 for advancing it out of position 17 into position 18 from which position it is immediately advanced into normal position over a circuit extending over the lower contact of cam 138, to ground at the left armature and back contact of relay 186. As soon as sequence switch 140 reaches position 1, with sequence switch 109 in position 16, a circuit is established through the magnet winding of sequence switch 109, through the lower contacts of cam 155, the right contacts of cam 145, to ground at the lett contact of relay 107, for advancing sequence switch 109 out of position 16 into position 18. TWith sequence switch 109 in position 18, the district selector 125 and line iinder 105 are released in the well known manner causing in turn the release of all other switching apparatus employed in the establishment of the connection. As soon as sequence switch 140 leaves position 17, the holding circuit through the windings oi: ratchetwheel relay 146 is opened and the ratchet wheel is immediately returned to its normal position. Relays 184, 132 and 144 are released when sequence switches 140 and 109 reach normal position in a manner which is obvious from the drawing.

It will now be assumed that sequence switch 109 is set into position 12, for establishing a talking circuit between the calling line and a wanted line in zone 2 of the exchange. When, therefore, sequence switch 140 passes from position 1 into position 17, during each revolution thereof, the previously traced circuit for the meter magnet 142 is established over the lower left contact of cam 143 in positions 2 to 4, and in addition, a circuit is established for the meter over the lower right contact 0f cam 148, positions 6 to 8, the outer left contact ot relay 134, lower left and upper right contacts of cam 108 to battery at the left contact of relay 106. Thus, for a connection established to subscribers lines in zone 2, the meter 142 is operated twice for each unit period of conversation.

It a connection is established to a line in zone 3 oi the exchange, the sequence swiich 109 will be set into position 11 for talking and in addition, relay 151 will be energized. r1`he energization of relay 151 is brought about at the time the oflice sender is controlling sequence switch 109 for talking selection by a circuit which extends from ground over cam 149 of the class sequence switch of the sender, which is closed only for calls into certain zones of the eX- change, the armature and front contact of advance relay 122 of the sender, wiper 124, conductor 150, winding of relay 151 to battery through the lower contact of cam 147. Relay 151, upon energizing, locks directly to ground through its right contact so that it is maintained after the sender has been dismissed from the established connection following the completion of talking selection. With relay 151 energized and sequence switch 109 in position 11, when sequence switch 140 passes from position 1 into position 17, the circuit of a meter 142 is closed three times, once over the lower lett contact of cam 143 in positions 2 to 4 and twice over the upper contact of cam 148, the left armature and contact of relay 151, the inner left contact of relay 134, and right contacts of cam 108 to battery at the left contact oirelay 106, while sequence switch 140 is passing from position 10 to position 12 and again from position 14 to position 16. Thus, for a call to a line in zone 3 of the exchange, the calling line meter is operated three times i'or each unit period of conversation.

Similarly, when a connection is established to a line in zone 4 of the exchange, the sequence switch 109 being set into position 12 and relay 151 being energized, the meter of the calling line is operated four times for each unit period of conversation, once as the sequence switch 140 passes through positions 2 to 4, once while it is passing through positions 6 to 8 and twice while it is passing through positions 10 to 12 and 14 to 16.

If the calling subscriber abandons the call before the district selector 125 has completed its selections and while the sequence switch 109 is in some position prior to position 7 the sequence switch 109 is advanced out of such position into position 16, awaiting t-he usual wipe-out of the connection, over a circuit extending from battery, through the sequence switch magnet 109,

lower contacts ot cam 155, the right cont-acts of cam 145 to ground at the lett contact ot relay 107.

That is claimed is:

1. In a telephone exchange system, a calling line, called lines, selective switches for extending the calling line to said called lines, a register mechanism, electrical means for variably setting'said mechanism, means controlled in accordance with the setting of said mechanism for selectively operating said switches, a meter for the calling line, and means dependent on the setting ot said mechanism for variably operating 'the meter for each unit period ot conversa.- tion.

2. In a telephone exchange system, a calling line a plurality of called lines located in different Zones, selective switches Jior er1-- tending the calling line to said called line, a register mechanism, electrical means for variably setting said mechanism, means controlled in accordance with the setting ot said mechanism for selectively operating` said switches, a meter, and means controlled by said mechanism in accordance with the zone in which the called line is located Vor variably operating the meter ter each unit period ot conversation.

3. In a telephone exchange system, selective switches for establishing telephone connections, a register mechanism, electrical means for variably setting said mechanism, means controlled in accordance with the setting` ot said mechanism for selectively operatingsaid switches, a meter, a timing switch arranged tobe driven repeatedly through its cycle ot operation, means controlled by the timing switch during each cycle ot operation tor operating the meter, and means controlled in accordance with the setting ot the register mechanism for varying` the number ot meter operations per cycle of said timing device.

4. In a telephone exchange system, a calling line, called lines, selective switches tor extending the calling line to said called lines, a register mechanism, electrical means Jfor setting said mechanism, means controlled inaccordance with said mechanism for selectively operating said switches, a meter for the calling line, a class switch for said mechanism, and means dependent upon the setting ot said class switch tor variably operating the meter for each unit period of conversation.

5. In a telephone exchange system, a calling line, selective switches tor extending connections from said line, a register mechanism, electrical means tor variably setting said mechanism for selectively operating` said switches, a meter, means for successively operating the meter at different rates during each unit period of conversation, and means dependent on the setting of said register mechanism for determining `the rate of operation ot said meter.

6. In a telephone exchange system, a calling line, a plurality ot called lines oit diterent classes, selective switches t'or extending the calling line to said called lines, a register mechanism, electrical means tor variably setting said mechanism, means controlled in accordance with the setting of said mechanism for selectively operating said switches, a meter, means tor successively operating the meter at different rates during each unit )cried of conversation, and means controlled by said mechanism in accordance with the class ot the called line tor determining the rate ot operation ot said meter.

7. ln a telephone exchange system, a calling line, plurality ot called lines located in ditierent zones, selective switches for extending the calling line to said called lines, a register mechanism, electrical means tor variably setting said mechanism, means controlled in ac"ordance with the setting 0In said mechanism for selectively operating said witches, a meter, means for successively operating the meter at dilferent rates during each unit period ot conversation, and means controlled by said mechanism in accordance with the zone in which the called line is located for determining the rate of operation ot' said meter.

d. In a telephone exchange system, a calling line, a plurality of called lines ot difterent classes, selective switches 'for extending the calling line to said called lines, a register aeehanism, electrical means for variably settine` said mechanism, means controlled in accordance with the setting of said mechanism for selectively operating said switches, inean, associated with one of said switches for altering the talking path thereover in accordance with the class ot the called line, a meter, and means controlled by said last amed means 'for variably operating the meter.

9. In a telephone exchange system, a callingv line, a plurality of called lines of different classes, selective switches tor extending the calling line to said called lines, a register mechanism, electrical means for variably setting` said mechanism, means controlled in accerdance with the setting of said mechanism for selectively operating said switches, means associated with one of said switches for altering the talking path thereover in accordance with the class of the called line, a meter tor the calling` line, a class switch 'tor said mechanism, and means dependent jointly upon the setting oit said class switch and upon said last named means for variablyoperating the meter in accordance with the class ot the called line.

ln witness whereof, I hereunto subscribe my name this 7 th day et August A. D., 1928.

LEWIS I-I. JOHNSON. 

